1. 1. Combine Wet Ingredients: In a large mixing bowl, whisk together the active sourdough starter, warm milk, granulated sugar, egg, melted butter, and vanilla extract until well combined and smooth. The mixture should be slightly bubbly from the active starter.

2. 2. Add Dry Ingredients: Gradually add the salt and 2 cups of the all-purpose flour to the wet ingredients, mixing with a wooden spoon or a stand mixer with a dough hook until a shaggy dough forms.

3. 3. Knead the Dough: Add the remaining 1 cup of flour, a little at a time, until the dough comes together and is no longer sticky. Transfer the dough to a lightly floured surface and knead for 5-7 minutes until it’s smooth and elastic. It should spring back slightly when poked.

4. 4. Incorporate Chocolate Chips: Gently knead in the chocolate chips until they are evenly distributed throughout the dough. Try not to overmix at this stage to avoid crushing the chocolate chips.

5. 5. First Rise (Bulk Fermentation): Place the dough in a lightly oiled bowl, turning it once to coat. Cover the bowl with plastic wrap or a clean kitchen towel and let it rise in a warm place for 2-3 hours, or until it has doubled in size. Alternatively, you can refrigerate it overnight (8-12 hours) for a slower, more flavorful rise.

6. 6. Shape the Rolls: Once risen, gently punch down the dough and turn it out onto a lightly floured surface. Divide the dough into 12 equal pieces. Roll each piece into a smooth ball and arrange them in a greased 9×13-inch baking dish, leaving a little space between each roll.

7. 7. Second Rise (Proofing): Cover the baking dish again and let the rolls rise in a warm place for another 30-45 minutes, or until they look puffy and have nearly doubled in size. Towards the end of this rise, preheat your oven to 375 F (190 C).

8. 8. Bake and Glaze: Brush the tops of the risen rolls with 2 tablespoons of melted butter. Bake for 20-25 minutes, or until they are golden brown on top and cooked through. While the rolls are cooling slightly, whisk together the powdered sugar and 1-2 tablespoons of milk to create a simple glaze. Drizzle the glaze over the warm rolls before serving.